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HYDRAULIC CIRCUIT OF CONSTRUCTION MACHINE

A hydraulic circuit of a construction machine includes: a first pump line that connects a delivery port of a pump to a pump port of a first direction-switching valve; a second pump line that is branched off from the first pump line and is connected to a pump port of a second direction-switching valve; and a priority valve provided on the second pump line. The priority valve is configured to: fully open the second pump line when a pressure difference between a delivery pressure of the pump and a load pressure of a first actuator is greater than a setting value; and decrease an opening degree of the second pump line in accordance with decrease in the pressure difference when the pressure difference is less than the setting value.

Tracked vehicle with steering compensation

A tracked vehicle includes a pilot control module which enables the pilot to steer the tracked vehicle using an existing joystick of the tracked vehicle. The tracked vehicle also includes a dual track drive pedal which drives the tracks of the vehicle simultaneously. The joystick is used to make steering corrections when utilizing the dual track drive pedal.

WORKING MACHINE

A working machine includes a hydraulic device, an operation valve to supply operation fluid to operate the hydraulic device and to vary the operation fluid to be supplied to the hydraulic device, an operation device having an operation member supported swingably, the operation device being configured to output an operation signal in accordance with an operation amount of the operation member, and a controller including a swing calculator to calculate an evaluation value representing a degree of swinging of the operation member, and a control signal generator to generate a control signal based on the evaluation value and the operation signal.

WORKING MACHINE
20210123214 · 2021-04-29 · ·

A working machine includes a switching valve to switch between a first state and a second state, the first state allowing a revolving speed of a traveling motor to be a first speed, the second state allowing the revolving speed of the traveling motor to be a second speed, and a controller device to reduce the revolving speed of the prime mover in either acceleration to switch from the first state to the second state or deceleration to switch from the second state to the first state. The controller device associates a return timing with a switch timing in either the acceleration or deceleration, the return timing allowing an actual revolving speed of a prime mover to start returning toward a first target revolving speed after the actual revolving speed is reduced, the switch timing allowing the switching valve to switch to either an acceleration side or a deceleration side.

WORK MACHINE AND METHOD OF CONTROLLING THE SAME
20210087791 · 2021-03-25 · ·

A controller controls a first drive source and a second drive source based on a moving speed of a motor grader measured by a speed sensor and a turning angular velocity of the motor grader measured by an IMU, to thereby independently control a rotation speed of each of a right front wheel and a left front wheel.

WORKING VEHICLE
20210047801 · 2021-02-18 ·

Provided is a working vehicle capable of increasing lifting operation speed of a working device without increasing cost, even when provided with a circuit configuration that prioritizes a steering operation over a working device operation.

A wheel loader 1 comprises a priority valve 451 configured to allow hydraulic oil discharged from a hydraulic pump 41 to flow into a steering drive circuit 43 preferentially over a working device drive circuit 44, and further comprises: an electric steering lever 30; a pair of solenoid control valves 34A, 34B configured to control a steering directional control valve 33; and a controller 5. The controller 5 is configured to control the pair of solenoid control valves 34A, 34B so as to limit operation speed of a steering 3 when determining that an engine 40 is in a low idle state and a lift arm 21 is performing a lifting operation.

Cruise control on a work machine

A cruise control system for work machines. The system comprises one or more levers for controlling the velocity of the work machine and one or more magnet assemblies. The magnet assemblies comprise means of overcoming the neutral bias of a control lever so that the velocity of the work machine may be maintained without manual input from the operator. The magnets may act directly upon a control lever or a surface adjacent a control lever. Additional controls may be employed to set a maximum cruising speed for the work machine when cruise control is engaged.

Method to select an active steering input device based on orbital pressure

A work machine having a cab coupled to a frame, a steering system coupled to the frame, a controller configured to selectively articulate the steering system, a joystick assembly positioned in the cab and in communication with the controller, a steering wheel assembly positioned in the cab and configured to selectively articulate the steering system, and a steering wheel sensor coupled to the steering wheel assembly and in communication with the controller to identify movement of the steering wheel assembly. Wherein, the controller does not articulate the steering system responsive to movement of the joystick assembly when the steering wheel sensor identifies movement of the steering wheel.

DRIVE MOTOR DISPLACEMENT CONTROL

A power machine can include a hydraulic drive system that includes an infinitely variable hydraulic drive motor. A run-time displacement of the hydraulic motor can be adjusted based on commanded travel speed or based on a output torque. In some case, the run-time displacement can be selected from one of a plurality of displacement ranges, such as a high range and a low range.

Utility Vehicle Having Adaptive Drive Limiting Control
20210062912 · 2021-03-04 · ·

A utility vehicle such as a loader includes a drive control system that includes an electronic controller and a manually actuated drive command device, such as one or more joysticks. The electronic controller is configured to control the drive control system to supply propulsive power at a predetermined output that is lower than that which is commanded by the drive command device for so long as an output of the drive control system is beneath a designated threshold, maintaining vehicle speed lower than a commanded vehicle speed. The electronic controller is further configured to control the drive control system to ramp up the propulsive power supply toward that which is commanded by the drive command device when the output of the drive control system is above the designated threshold, causing the vehicle speed to approach a commanded vehicle speed. The vehicle may include a EH drive system such as a hydrostatic drive system.